Gas supply control system



Aug. 28,- 1934. .G. A. TUCK @As SUPPLY CONTROL sYsTEM Filel Aug. 1o.V1951 Patented Aug. 2s, i934 UNITED STATES PATENT OFFICE Thisinventionrelates generally to systems for eiecting control of the supplyof gaseous fuel to gas heaters, as for example to domestic heatingfurnaces. v

5 In connection with gas heaters it has previously been proposed toprovide a valve connected in the gas supply line, which is automaticallyclosed in the event the pilot 'ame becomes extinguished. The advantagesto be gained by such an arrangement are obvious, in that where theheater is.

controlled from a 'remote point, the possibility of introducing largeamounts of gas into the furnace thru the main burner when the pilot isextinguished, is precluded. Prior systems of this character have had thedisadvantage that they are difficult to install upon'existing heaters.It frequently happens that in variously proposed installations, variousparts, as for example the main or primary control valve, must be solocated as to meet peculiar requirements and conditions, and theserequirements and conditions will vary with different installations. Thusunless the arrangement of parts can beV readily shifted for diilerentinstallations, the cost of making installations upon prevailing systemswill be relatively high.

It is an object of the present invention to devise an automatic systemof the above character which can be readily installed with slightexpense on prevailing gas heaters, and which will enable variousarrangements of parts to suit varying conditions.

, It is a further object of the invention to devise such a system whichwill be characterized by simplicity of operation, and by reliabilityunlder actual working conditions.

Further objects of the invention will appear from the followingdescription in which the preferred embodiment of the invention is setforth in detail in conjunction with the accompanying drawing. It is tobe understood that the appended claims are to be accorded a range ofequivalents consistent with the state of the prior art.

Referring to the drawing: Figure 1 is a side elevational view, partly incross section, illustrating a system incorporating the presentinvention.

Fig. 2 is a cross sectional detail, in side eleva-v tion, illustrating apilot burner such as is preferably utilized in my system.

The system and apparatus illustrated in the drawing consists of a mainor primary gas valve 10,-in conjunction with a secondary valve 11. -Theparticular type of primary valve 10 illustrated consists of a valvecasing 12 having its in- (Cl. 15S-117.1)

flow side adapted for connection with a gas supply pipe line 13, andits'outilow side adapted to be connected with a pipe 14 which leads'to aburner of a gas heater. A valve member 16 of the poppet type is disposedWithin valve casing 12, and cooperates with the valve seat 17. A stem 18extends downwardly from valve member 16, and at its lower end stem 18 isconnected to the cent-er of a flexible diaphragm 19. The lower portion21 of valve casing l2 is enlarged to embrace the upper side o!.diaphragm 19. The peripheral edge portion of diaphragm 19 is shownclamped between casing portion 21, and

a lower cover 22. Thus a fluid chamber 23 is formed above the diaphragm.In order to seal chamber 23 against flow of gas about stem 18, I haveshown a smaller diaphragm 24 having its` outerV peripheral portionsecured to and sealed with respect to the casing portion 21, and havingits innerv portion secured to and sealedl to stem 18. In order tonormally bias stem 18 and valve member 16 upwardly toward closedposition, I provide a compression spring 26. The upper end of thisspring is shown seated upon the lower end of stem 18 below diaphragm 19,while the lower end of the spring is positioned within a socket orrecess 27 formed in the center of cover 22. By means of a set screw28,the tension upon spring 26 can be adjusted.

With respect to the secondary valve means l1, the body portion 31thereof is formed as'an integral portion of the primary valve casing 12as illustrated, and is' provided with a cylindrical bore 32 and alsowith gas ducts 33 and 34. Duct 33 communicates with the inflow side ofvalve l0 about stem 18, and with bore 32, while duct ',34 communicatesbetween bore 32 and the fluid chamber 23. Slidably positionedwithin bore32 there is a movable valve member 36, which can be in the form of acylindrical plug.

Associated with the apparatus described above, there is a pilot burner37, a preferred form of which is illustrated in Fig. 2. This burner isof course located in the combustion chamber of the gas heater, and canbe conveniently carried by a bracket 38. In the form illustrated in Fig.2 it consists of an enlongated tube or pipe having a gas vent 39 formedin its inner end, and having additional apertures 41 formed along itslower side for escape of gas. Holes 4l are preferably arranged at anangle to the axis of the burner, so that the ame from one hole will tendto overlap and ignite gas issuing from an adjacent hole.

Toprovide a thermostatic element cooperating with pilot burner 37, Iprovide a bimetallic strip 43A which extends in spaced relationshipbelow burner 37, and which has its one end fixed to bracket 38. Theupper surface of strip 43 is exposed to radiation from the flame ofburner 37, so that when the burner is lighted, the strip 43 is heated tocause it to ex to a positionshown in solid lines in Fig. 1. -Whentheflame of the pilot burner is extinguished or is abnormally low, strip43 cools and assumes a positionsuch as shown in dotted lines. To providea mechanical connection between strip 43 and the movable secondary valvemember 36, yI utilize a ilexible wire 44, made of suitable material suchas steel, one end of this wire being connected to the freeexid of strip43, the other end being connected to valve member 36. This wire ispreferably protected by a exible casing or tube 46. Where the wireenters the bore 32 leakage canbe prevented by suitable means such as apacking gland 47.

To supply gas to the pilotburner 37 a tube 47` is shown having its oneend connected to the pilot burner and its other end communicatingwith'the gas duct 34. To enable lighting pilot burner 37 I have shown asmall burner 48 located near the forward end of pilot burner 37, and

' which 'is connected by tube 49to the gas duct 33.

By means of a gasv cock or valve 5l the iiow of gas to burner 48 may bemanually controlled.

In installing my control lsystem primary valve 10 is suitably locatedoutside the heater, while bracket 38 together with pilot burner 37 andthermostat strip 43 is located within the combustion chamber in suchposition that the pilot burner will readily ignite gas flowing from themain burner of the heater. Generally a solenoid or electrical motoroperated valve, controlled as by means of an electrical thermostat froma remote point, is interposed in the gas supply pipe 13, A manual gascock' 52 can also be interposed in this line, in order to permanentlyshut orf supply of gas to theprimary valve 10 and to the pilot landmainburners. Flexible wire 44 is connected between the thermostat strip43 and mbvable valve member 36, and the length of this wire is.

such that when Astrip 43 is heated and in a position such as shown insolid ,linesl in Fig. 1, valve" .member 36.will be in a' correspondingposition such as shown in solid lines )in this gure. However whenstrip43 is not heated and a'ssum's a position such as shown in dotted lines,valve member 36 is vmoved to a position in which it interruptscommunication between gas ducts 33 and 34.'

Operation of the system can be briefly outlined as follows:-When the.heateris operating normally and gas from pilot burner 37 is' ignited,primary valve member 16` is in open position as shown in Fig. l.Thermostatic strip-.43 is at an elevated temperature by virtue of heattrans- .ferred to it by radiation i'rom the flame ofpilot burner 37,Y sothat it is flexed as illustrated in solid lines. Secondary valve member36 is likewise in tlie position illustrated, so that gas from the inflowside of primary valve 10 is free to exert a -pressure thru gas ducts 33and 34, in chamber 23. This ipressure in chamber 23 acting upondiaphragm 19, serves to retain primary `valve member 16 open. Assumingnow that ,the

tion such as shown in dotted lines. Suchmove- ,Y ment of thermostatstrip 43 causes a corresponding movement of secondary valve member 36 to-lmtemiut A communication between gas ducts "33 der pressure and the.outiiow side being adapted primary valve member, means forming a closedand 34. Thus further flow of gas from the inflow side of vvalve 10 topilot burner 37 is interrupted, and gas pressure in chamber 23 isimmediately reduced to atmospheric because at this time it is ventedthru the pilot burner; The force of spring 26 simultaneously forcesvalve member- 16 to closed position, to'interrupt further supply of gasAfrom pipe 13. Under suchV conditions it is of course impossibletosupply gas to the main burner of the heater, orto the pilot burner 37.To return the system to normal operating condition, the operatorsupplies gas to burner 48 by turning cock 51', and ignites this. burner.The ilame from burner 48.heats thermostatic strip'43, thus causing thisstrip to again ilex downwardly to move secondary valve member 36 to aposition to again establish communication between gas ducts 33 and 34.When this communicationis again established, gas is again supplied'topilot burner 37, which is then ignited by the flame from burner 48, andthe primary valve member 16 is' also moved to open position by virtue ofthe pressure of gas introduced into chamber 23, so that gas can beagain. supplied to the main burner of the heater.

It isA characteristic of my system that the primary valve is shut off byan abnormal reduction of gas pressure, such as would reduce the pilotflame to a point at which the main burner might not be properly.ignited. This feature is 105 tions, the inflow side oi said primaryvalve being adapted for (connection with a source of gas unforconnection with a 'gas burner, spring means vfor normally` biasing saidvalve member toward closed position, a diaphragm connected with saidfluid chamber upon one side of said diaphragm whereby when gas underpressure is introduced' into said chamber. ilexing oi" said' diaphragmeects opening movement of said primary valve member, secondary valvemeans including a movable valve member, a gas duct serving to connectsaid secondary valve means with the inilow side of said primary valve, asecond gas ductA serving to connect said secondary valve means with saidclosed uid chamber, said secondary vmovable valve member being operableto cut olif` communication between said gas ducts in one position of-the same and to permitr communication between' said ducts 4ilor another*position'of the same, a pilot gas burner having. uninterrupted 185.

communication with said second mentioned gas duct, a bimetallic stripassociated with said pilot f burner, and an elongated wire serving .as amechanical motion'transmitting connection between said strip and saidsecondary valve member, one end of said wire being connected to saidstrip and the other: end being connected with said secondary valvemember` 2. In a gas supply control system for gas heaters, a primary gasvalve including a valvewmember movable between vopen and closedpositions, the iniow side of said primary valve being adapted forconnection with a source Aof gas under pres- .sure and the outilow sidebeing adapted for con- I nection with a gas burner, spring means fornormally biasing said valve member toward closed position, a diaphragmconnected with said primary valve member, means forming a closed uidchamber upon one side of said diaphragm whereby when gas under pressure'is introduced into said chamber fiexingof said diaphragm effects openingmovement of said primary valve member, secondary valve means including amovable valve member, a gas duct serving to connect l0 said secondaryvalve means with the iniiow side oi' said primary valve, a second gasduct serving closed uid chamber, said secondary movable 3 valve memberbeing operable to cut oil communication between said gas ducts in oneposition of the same and to permit communication between -cation withsaid second mentioned gas duct, a

temperature responsive -means associated with -said ducts for anotherposition of the same, a

said pilot burner, and means forming a mechanical motion transmittingconnection between Vsaid temperature responsive means and said secondarymovable valve member. to Lconnect said secondary valve-means with said lGEORGE A. T UCK.

1.25 lao. Y

